1. Field of the Invention
The present invention relates to an image forming device in which a process unit having devices related to an electrophotographic process can be inserted into or removed from a device main body. More specifically, the present invention relates to an image forming device having a lock mechanism for fixing a position of a process unit inserted in a device main body.
2. Description of Related Art
In an image forming device which forms a toner image on paper by an electrophotographic process, devices related to the electrophotographic process are unitized as a single unit or a plurality of collective units. The process unit is provided capable of being inserted into and removed from the device main body. As such a process unit, for example, there are a drum unit having a photoconductive drum, a toner unit accommodating toner and a fixing unit having a fixing device. By providing the process unit capable of being inserted into or removed from the device main body, each process device can be replaced easily. Therefore, even when a user is not a service person, the user can carry out a replacement operation of the process device. As a result, maintenance of the image forming device is improved.
In the above-described image forming device, the image quality is required to be maintained in a highly accurate manner. Therefore, when the process unit is inserted into the device main body, a position of the process unit is required to be fixed accurately in the device main body. A description will now be made of a conventional technique relating to the fixing of a position of the process unit. According to the conventional technique, the process unit is provided capable of being inserted into and removed from a device main body. When a cover of the device main body is closed, a gripper of the process unit makes contact with the cover and the position of the process unit is fixed. In particular, according to this conventional technique, since the gripper is formed with an elastic body, when fixing the position of the process unit with respect to the device main body, a high degree of accuracy is not required for a clearance between the process unit, which is to be replaced, and the device main body.
According to the above-described conventional technique, when the cover of the device main body is closed, the position of the process unit is fixed. Therefore, each time when the cover is opened, the fixing of the position of the process unit is released. In particular, the cover of the device main body is opened and closed not only when replacing a specific process unit but also when removing jammed paper or removing another process unit. If the fixing of the position of the process unit is released each time when the cover is opened, a mechanism for fixing the position of the process unit deteriorates unnecessarily.